TCP J21290156+3631056: new transient (11.5 mag) in Cygnus

Affiliation

Association Française des Observateurs d'Étoiles Variables (AFOEV)

Thu, 03/22/2018 - 22:54

TCP J21290156+3631056 (UG:)

RA 21h29m01.56s, DEC +36°31'05.6" (J2000.0)
2018 Mar. 22.7846 UT, 11.5 mag (CCD, unfiltered)
Discoverer: Tadashi Kojima (Gunma-ken, Japan)

2018 03 22.785 UT
Discovered by T. Kojima, Gunma-ken, Japan, on three frames with five second exposure using Canon EOS 6D digital camera + 200-mm f/3.2 lens under the limiting mag = 13.8, who writes nothing is visible at this location on the previous frame (limit mag = 13.5) taken 2018 Mar. 16.783 UT. There is a star (mag = 16.7) at 01s.72 and 06".9.

2018 03 22.93 UT
The abovementioned star of 16.7 mag is USNO-A2.0 1200-18025481. There are many other designations for this star (G= 17.19 mag in Gaia DR1), e.g. USNO-B1.0 1265-0493972, GSC2.3 N359016841 (V= 17.39 mag), XPM 253-0794263, 2MASS J21290156+3631049, 1RXS J212902.0+363103.
No previous outbursts or eruptions were recorded by the ASAS-SN Sky Patrol (Shappee et al. 2014ApJ...788...48S and Kochanek et al. 2017PASP..129j4502K) between 2015 March and 2017 November (latest available observation 2017-11-22.247 UT):
https://asas-sn.osu.edu/light_curves/3083fd37-af79-48f5-9509-6e5e1bb30b…
--- Patrick Schmeer (Saarbrücken-Bischmisheim, Germany)

Follow-up reports:
http://www.cbat.eps.harvard.edu/unconf/followups/J21290156+3631056.html

Spectroscopy, time-resolved photometry, and precise astrometry are urgently required.

Clear skies,
Patrick

FRF

Affiliation

Magyar Csillagàszati Egyesület, Valtózocsillag Szakcsoport (Hungary) (MCSE)

Fri, 03/23/2018 - 00:09

Finally on the Northern Sky

Finally a bright transient on the Northern Sky.

Until ~22 UT the sky was more-or-less clear in Budapest, but now it overcast :(
I hope someone on other part of the planet can make follow-up observations soon.

Clear skies,

Robert